Control system for a derrick

ABSTRACT

A derrick having hydraulically operable remote control and main control systems wherein the remote control system is separate from and hydraulically non-communicative with the main control system. The remote control system employs a hydraulic fluid that differs from that used in the main control system such that the most desirable fluid characteristics for each system can be independently selected.

United States Patent [191 Balogh CONTROL SYSTEM FOR A DERRICK [75]Inventor: Roy Balo g h,l adue,ly1 o [73] Assignee: McCabe-Powers BodyCompany,

St. Louis, M0.

221 Filed: Apr. 24, 1972 1211 Appl. No.: 247,017

{52] US. Cl 182/148, 182/2, 91/412, 60/36 [51] Int. Cl B661 11/04, EO4g1/18 [58] Field of Search.. 182/2, 141, 148; 91/412, 414; 60/545, 36

[56] References Cited UNITED STATES PATENTS 3,378,103 4/1968 Zwightetal..1s2/2 Jan. 29, 1974 10/1952 Camerota 91/412 2,648,949

8/1953 Taylor 60/545 R Primary Examiner-Reinaldo P. Machado Attorney,Agent, or FirmJohn D. Pope 57 ABSTRACT A derrick having hydraulicallyoperable remote control and main control systems wherein the remotecontrol system is separate from and hydraulically noncommunicative withthe main control system. The remote control system employs a hydraulicfluid that differs from that used in the main control system such thatthe-most desirable fluid characteristics for each system can beindependently selected.

27 Claims, 1 Drawing Figure 1 CONTROL SYSTEM FOR A DERRICK Thisinvention is directed to new and useful improvements in derricks andmore particularly to hydraulic control means for controlling operativemovement of a derrick at a work site.

The beam assembly-of a derrick is generally hydraulically acutatedthrough hydraulic work cylinders, movement of which is controlled by ahydraulic control system. The beam assembly is generally equipped withone or more hydraulically actuated accessories such as winches, polepullers, jib booms and augers, to name a few. It is often desirable torotate the beam assembly and to accomplish this the beam assembly isusually secured to a turret-mounted mast assembly, which turret isordinarily rotatable by ahydraulic motor. Outriggers which help maintainthe derrick in a stable position during movement of the aforementionedcomponents are also usually hydraulically actuated in and out of adesired position.

Generally all the hydraulically operative parts of a derrick arecontrolled at a main control station accessible to one workman. The maincontrols normally include a main hydraulic circuit that actuates thework cylinders of the operating components. If the derrick includes awork station such as a basket or elevated platform, one or more of thederrick components usually have a remote control operable by a workmanat his work station. The remote controls generally comprise one or morehydraulic fluid lines forming a hydraulic network that is incorporatedinto the main control hydraulic circuit with both the main and remotecontrol lines being hydraulically communicative with one another andoperating from a common fluid source.

Since the fluid lines in the remote control network do not operate workcylinders, the fluid pressures, fluid line diameters, and fluidcapacities are substantially less than the pressures, line diameters,and capacities of the main control fluid lines that feed the workcylinders. For example, a known main control fluid line generally has aninternal diameter of one-half inch and experinces fluid pressures of2,500 p.s.i., whereas the remote control fluid lines incorporated in themain control system generally have an internal diameter ofthree-sixteenths of an inch and experience fluid pressures of 200 p.s.i.Due to this difference in fluid line cross-section and capacity, theviscosity of the hydraulic fluid used directly affects the response ofthe remote control system, especially in cold winter temperatures. Thusa control system which can be remotely operated at a given response rateone day often operates at a completely different response rate onanotherday. This inconsistency of response rate is often unpredictabledue to unpredictable changes in temperature and can cause damage andinjury to the derrick, the derrick operators, or the equipment beingserviced by the derrick.

Among the several objects of the present invention may be noted theprovision of a novel control system for a derrick wherein remote controlfluid lines are hydraulically isolated and non-communicative with maincontrol fluid lines; a novel derrick having one type of hydraulic fluidfor the remote control system and another type of hydraulic fluid forthe main control system; a novel derrick having hydraulically operableremote control valves mechanically connected to main control valves ofthe main control system; a novel derrick having a remote controlhydraulic system that includes a pump driven by a hydraulic motor in themain control system; and a novel method for remotely controllingmovement of derrick beams and other hydraulically actuable components.Other objects and features will be in part apparent and in part pointedout hereinafter.

The present invention relates to a novel derrick wherein a remotecontrol hydraulic system is hydraulically separate from andhydraulically noncommunicative with a main control hydraulic system. Afirst fluid having one set of fluid characteristics such as fixedviscosity is used in the remote control'system whereas a second fluidhaving another set of fluid characteristics such as excellent lubricityis used in the main control system. The main control system includes abank of manually operable main valves having movable members, which mainvalves are connected by fluid lines to hydraulic work cylinders. Themain control system also includes a hydraulic motor that is rotatable inresponse to movement of fluid pumped through the main control systemfluid lines by a main power pump. The remote control system includes abank of manually operable master valves hydraulically connected to abank of slave valves having movable members mechanically interconnectedto the movable members of the main valves. Movement of a remote controlmaster valve member causes movement of a corresponding slave valvemember, the slave valve also movingthe main valve member to actuate acorresponding work cylinder, thereby moving one of the hydraulicallyactuated components of the derrick.

The remote control system also includes a pump that is drivinglyconnected to the hydraulic motor in the main control system such thatmovement of the remote control pump is attributable .to movement of thehydraulic motor, which motor derives its movement from the main powerpump.

The invention accordingly comprises the constructions and methodshereinafter described, the scope of the invention being indicated in thefollowing claims.

In the accompanying drawing, in which one of various possibleembodiments of the invention is illustrated, the FlGUREof the drawingshows a schematic diagram of the remote control system and main controlsystem of the present invention superimposed on a phantom outline of aderrick beam assembly, mast as- I sembly and turret.

Corresponding reference characters indicate corresponding partsthroughout the drawing.

Referring to the drawing, a derrick incorporating one embodiment thereofis generally indicated in phantom outline by reference numeral 10.Derrick 10 symbolically represents a derrick having an articulated beamassembly such as is disclosed in U. S. Pat. No. 3,378,103.

Derrick 10 includes an outer beam 12 having a work basket 14 at the freeend thereof, the opposite end of beam 12 being pivotally secured to aninner beam 16. Outer beam 12 is of any suitable known construction suchas disclosed in U.S. Pat. No. 3,378,103. Work basket 14 is also of anysuitable known construction such as is disclosed in U.S. Pat. No.3,154,199. Inner beam 16 is in turn pivotally secured to -a mastassembly 18 that is mounted on a rotatable turret 20. Inner beam 16,mast assembly 18, and turret 20 are of any suitable known constructionsuch as disclosed in U. S. Pat. No.

' any suitable known construction such as disclosed in U. 8. Pat. No.3,396,852 is joined to inner beam 16 and mast assembly 18 forarticulation of inner beam 16 with respect to mast assembly 18.

Derrick further includes a main control system generally indicated byreference numeral 30 and a remote control system generally indicated byreference numeral 100. Both control systems are hydraulically operable,and for purposes of distinction therebetween the fluid lines of maincontrol system 30 have been represented by the bolder lines in thedrawing.

Main control System30 comprises a fluid supply tank 32 containing asuitable hydraulic fluid such as oil derived from petroleum, tank 32being connected in series on a fluid line 34 to a known shutoff valve 36which is in turn connected-in series to a known fluid filter 38. Theoutput of filter 38 is connected in series to any suitable known mainpower pump 40 for pumping fluid such as a Vickers part No. V2l0-8-lG-12-S49. A known check valve 42 and a known fluid filter 44 areconnected in series on the output side of pump 40. Fluid in line 34 ispumped by pump 40 through a main control valve inlet line 46 that isconnected to a twoway, three-position main control valve 66 of anysuitable knownconstruction. A main control valve outlet line 56 connectsvalve 66 to a main control valve inlet line 58 that joins to a two-way,three-position main control valve 68. Similarly, a main control valveoutlet line 60 connects valve 68v to a main control valve inlet line 62that joins a two-way, three-position main control valve 70. A maincontrol valve outlet line 64 connects valve 70 'to a tank return line 48having a check valve 50 and a hydraulic motor 52 connected thereto. Maincontrol valves 66, 68, 70, are identical and include a manually operablecontrol handle 72 for actuating a movable valve mmber 74 which extendsinside valves 66, 68, 70. Control handles 72, 72, 72,- can be maintainedin a predetermined neutral reference position by biasing means such as aspring 76.

Pairs of operating lines 78 80 and 82, 84, interconnect main valves 68and 70 with work cylinders 24 and 22.- A similar pair of operating lines86, 88, interconnect main valve 66 with a rotation motor 90 on turret20.

In operation of main control system 30 shutoff valve 36 is opened andpump 40 is set to operate. Fluid from tank 32 is drawn through filter 38and pumped through check 'valve 42 and filter44 into main control valveinlet line 46. When movable members 74, 74, 74, of main control valves66,68, 70, are in a neutral or unactuated position operatinglines 78,80, 82, 84 and 86,

88 are blocked at their respective valves 68, 70, and 66.

of movable valve member 74 enables fluid to enter valve through feederline 62 and to pass outwardly of valve 70 to cylinder 22 throughoperating line 82. Fluid in line 82 causes cylinder 22 to be movablyactuated in a manner such as disclosed in U. S. Pat. No. 3,396,852,which actuation causes fluid to pass from cylinder 22 back to maincontrol valve 70 through operating line 84. This returning fluid passesoutwardly of main valve 70 through outlet line 64 into tank return line48.

If it is desired to articulate beam 12 in a reverse direction, controlhandle'72 of main valve 70 is pivoted in a second direction to movemovable valve member 74 to a second predetermined position enablingfeeder line 62 to pass fluid outwardly of valve 70 through operatingline 84. Fluid returns from cylinder 22 to main valve 70' throughoperating line 82 and passes outwardly of main valve 70 through outletline 64 into tank return line 48. Main valve 68 operates cylinder 24 inan identical manner. Main valve 66 also operates the same as valves 68and 70 but fluid passing out of valve 66 into operating line 88'causeshydraulic motor 90 to rotate in one direction, fluid returning frommotor 90 to valve 66 through line 86. Motor 90 is rotatable in a reversedirection when the flow paths in operating lines 86 and 88 are reversedby main control valve 66. Under this hydraulic circuit arrangement it isdesirable to operate only one of the main valves 66, 68 and 70 at a timealthough the circuit can be modified to permit simultaneous operationthereof. In the present hydraulic arrangement, when one of the mainvalves 66, 68, or 70 is being actuated, the other unactuated maincontrol valves permit fluid to flow therethrough without entering theassociated operating lines.

Remote control system comprises a fluid tank 102 containing a suitablesilicone oil such as Dow Corning 50 centistokes. This type of siliconeoil is a synthetic compound having a relatively flat viscosity curve forwide ranges of temperature when compared with the viscosity curve of oilderived from petroleum. It should be noted that silicone oil hasrelatively poor lubricating qualities in comparison with the lubricityof oil. derived from petroleum. Also at present silicone oil is verymuch more expensive than petroleum-derived oil. Nevertheless theviscosity characteristics of silicone oil make it highly desirable forthe purposes of the present invention.

Fluid tank 102 is connected in series with a known shutoff valve 104 anda known suction filter 106, the outlet of which is fed into a suitablepump 108 such as Eastern part No. l02-F21-QIA. A flexible coupling 110interconnects pump 108 with hydraulic motor 52 1 in main control system30. A known filter 112 is connected to the output side of pump 108,which filter passes fluid to a line junction 114.

A master valve distribution line 116 interconnects junction 114 to abank 118 of three master valves 120, 122 and 124. Each master valve 120,122, 124, comprises a pair of two-way, two-position valves 126, 128, ofknown construction, valves 126, 128, having movable members 130, 132,projecting from an end thereof toward a respective valve acutator handle134, 136, 138. Actuator handles 134, 136, 138, are pivoted intermediateeach pair of valves 126, 128, at a pivot point and include oppositelyextending valve member displacer arms 142, 144, arranged to engagemovable members 130, 132. Movable members 130, 132, are

maintained in a predetermined reference position by ahaving inlet lines154, 156, arranged to pass fluid into valves 126 and 128, respectively.

Remote control system 100 also includes return line means for returningfluid from valve bank 118 to tank 102. The return line means comprise apair of outlet lines 158, 160, extending from valves 126, 128,tojunction lines 162, 164, 166, that are respectively connected to amain return line 168 connected to tank Remote control system 100 furtherincludes a bank of three identical slave valves 170, 172, 174, having amovable piston member 176 and two valve chambers 178 and 180. Movablepiston members 176, 176, 176, are mechanically connected (not shown) tomovable members 74, 74, 74, of main control valves 66, 68, and 70 andmaintained in a predetermined neutral reference position by biasingmeans such as a spring 182 provided on member 176.

Remote control system 100 additionally includes a first bridge line 184having a pressure relief valve 186 thereon, which line interconnectsjunction 114 to slave valve distribution means for distributing fluid toslave valves 170, 172 and 174. The slave valve distribution meansinclude a main distribution line 188 having feeder lines 190, 192, 194,that connect to pairs of inlet lines 196, 198, 200, 202, and 204, 206,which inlet lines pass fluid toslave cylinder chambers 178 and 180,respectively. Known check valves 208 are provided on each inlet line. Afirst operating line 210 connects slave cylinder chamber 178 of slavevalve 170 with valve 128 of master valve '120and a second operating line212 connects slave cylinder chamber 180 with valve 126. Operating linepairs 214, 216, and 218, 220, similarly connect slave valves 172, 174,to master valves 122, 124, respectively. 8

Remote control system 100 also includes a second bridge line 222 havinga known check valve 224 thereon, which bridge line extends from firstbridge line 184 and main distribution line-188 to return line 168.

In operation of remote control system 100 shutoff valve 104 is openedand pump 108 is set into operation. Movement of pump 108 is attributableto rotation of hydraulic motor 52 in main control system 30, the rota-'tion of motor 52 being transmitted to pump 108 through flexible shaft110. Fluid from tank 102 is drawn through filter 106 and pumped throughfilter 112 to master valve distribution line 116 and first bridge line184. Fluid in first bridge line 184 passes through pressure relief valve186 and thereafter flows through slave main distribution line 188 andsecond bridge line 222. Fluid in second bridge line 222 passes throughcheck valve 224 to return line 168 for passage to tank 102.

When remote control handles 134, 136, 138, are not being ctuated, thefluid in master valve distribution line 116, feeder lines 148, 150, 152,and inlet lines 154, 156, is blocked from entering valves 126, 128, ofmaster valves 120, 122 and 124. During such blockage the fluid. in slavevalve mainline 188 passes through feeder lines 190, 192, 194, inletlines 196, 198, 200, 202, 204, 206, and their respective check valves208 into slave cylinder chambers 178,180. Fluid exits from slavecylinder chambers 178, 180, into operating lines 210, 212,

214, 216, 218, 220, for passage into a respective valve 128, 126, ofmaster valves 120, 122, 124. Fluid exits from valves 126, 128, to outletlines 158, 160, junction lines 162, 164, 166, and main return line 168.During this movement of fluid through slave cylinder chambers 178, 180,and valves 126, 128, of master valves 120, 122, 124,. movable members130, 132, thereof are maintained in a fixed reference position bysprings 146. This fluid movement continuously bleeds slave valves 170,172, 174, and master valves 120, 122, 124, even when main controlhandles 72, 72, 72, of main control valves 66, 68, 70, are beingoperated. Thus there is complete purging of air in remote control systemand any oil which may have been lost, as in periods of inactivity, isrestored. This bleeding function occurs automatically with the startingof power pump 40 and continues as long as pump 40 is running. Furtherthe back pressure of the bleed flow is not'high enough to overcomebiasing springs 76 or 182 and cause movement of movable members 74 or176 should pressure fail in either slave cylinder chamber 178 or 180.The

main control and remote control systems 30, 100, are automaticallyindexed to a predetermined neutral reference position by springs 76 and182.

If it is desired to articulate outer beam 12' away from inner beam 16through remote control system 100, handle 138 of master valve 124 ispivoted to permit arm 144 to move member 132 of valve 128 to apredetermined position. This moved position of member 132 prevents fluidfrom passing outwardly of valve 128 into outlet line 160, junction line166 and return fluid line 168. Fluid enters valve 128 of master valve124 from main distribution line .116, feeder line 152, and inlet line156,'and passes outwardly thereof to operating line 218 for transmissionto cylinder chamber 178 of slave valve 174. Fluid accumulates incylinder chamber 178 due to the presence of check valve 208 on line 204,which fluid accumulation causes movable member 176 to displace. Sincemovable members 176 and 74 are mechanically interconnected, member 74also displaces, thereby enabling fluid to pass through operating line 82to actuate cylinder 22 in a manner previously described.

It should be noted that when valve 128 is actuated and arm 142 of remotecontrol handle 138 is not in engagement with movable member of valve 126there is continuous bleeding of valve 126 and cylinder chamber of slavevalve 174 in a manner previously described.

To articulate outer beam 12 toward inner beam 16, remote control handle138 is pivoted in a reverse direction such that arm 142 moves movablemember 130 of valve 126 to a predetermined position wherein valve 126prevents fluid from passing outwardly thereof into 7 lines 158, 166 and168. Fluid enters valve 126 through main distribution line 116, feederline 152 and inlet line 154', and passes outwardly of valve 126 tooperating line 220. The fluid in operating line 220 feeds cylinderchamber 180 of slave cylinder 174, accumulating therein due to thepresence of check valve 208 on line 206. This fluid accumulation.displaces slave valve member 176 and control valve member 74 while slavecylinder chamber 178 and valve 128 are being continuously bled. Movementof member 176 enables fluid to pass through control'valve 70 throughoperating line 84 to actuate cylinder 22 in a reverse direction. Mastervalves 122, 120, can also be actuated in an identical manner by movingremote control handles 136 and 134 to respectively articulate inner beam16 with respect to mast assembly 18 and to iii-directionally rotatehydraulic motor 90 for rotation of turret 20.

As will be apparent. to those skilled in the art the present hydrauliccontrol system can be arranged to rates beyond a predetermined level topass through the bypass relief valve instead of hydraulic motor 52. Thiswill insure that motor 52 and pump 108 run within a predetermined speedrange regardless of the rate of fluid flow in the main control system.As an alternative to the motor 52 pump 108 arrangement, remote controlsystem 100 can be independently powered by a separate power pump (notshown).

Some advantages of the novel derrick evident from the foregoingdescription include a remote control system that has a consistent rateof response over a wide range of temperatures, a remote control systemthat is hydraulically separate and non-communicative with the maincontrol system such that a breakdown of the remote control system doesnot necessitate shutdown of the main control system, and a remotecontrol system and maincontrolsystem which can each operate withdistinctly different hydraulic fluids such that the .most desirablefluid characteristics for each system can be independently selected. I

.In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous resultsattained.

As various changes could be made in the above constructions and methodswithout departing from the scope of the invention, it is intended thatall matter contained in the above description or shown in theaccompanying drawing shall be interpreted as illustrative and not inalimiting sense.

What is claimed is:

1. An aerial device comprising a movable beam member having a hydrauliccylinder connected thereto, actuation of said cylinder moving said beam,first control meansprovided at one station on said aerial device forcontrolling actuation of said hydraulic cylinder, and remote controlmeans provided at a second station on said aerial device for actuationof said first control means, said first control means comprising a firsthydraulic circuit having first hydraulic fluid supply means forsupplying fluid to said first hydraulic circuit, said remote controlmeans comprising a second hydraulic circuit having second hydraulicfluid supply means for supplying fluid to said second hydraulic circuit,said first and secondfluid supply means being noncommunicative with oneanother, and said first and second hydraulic circuits beingnoncommunicative with one another such that fluid from said firsthydraulic circuit does not flow into said second hydraulic circuit andfluid from said second hydraulic circuit does not flow into said firsthydraulic circuit.

2. An aerial device as claimed in claim 1 wherein said first and secondhydaulic fluid supply means each contain different hydraulic fluids.

3. An aerial device as claimed in claim 2 wherein the hydraulic fluid ofsaid first hydraulic fluid supply means is petroleum oil and thehydraulic fluid of said second hydraulic fluid supply means is siliconeoil.

4. An aerial device as claimed in claim 1 wherein said first hydrauliccircuit includes a first hydraulic motor, said second hydraulic circuitincluding a pump for pumping fluid through said second hydrauliccircuit, said pump being drivingly connected to said first hydraulicmotor such that pump movement is attributable to movement of saidhydraulic motor.

. 5. An aerial device as claimed in claim 1 further including slavevalve means having a valve member mechanically connected to said firstcontrol means, said slave valve means having hydraulic communicationwith said second hydraulic fluid supply means such that fluid in saidsecond hydraulic circuit passes through said slave valve means andmovement of said slave valve member by said second hydraulic fluideffects movement of said first control means through said mechanicalconnection to actuate said hydraulic cylinder thereby moving saidmovable beam.

6. An aerial device as claimed in claim 1 wherein said first station isspaced from said beam and said second station is associated with saidbeam.

7. An aerial device as claimed in claim 6 wherein said second stationcomprises a basket connected to said beam.

8. An aerial device as claimed in claim 1 further including a rotatableturret for supporting and rotating said movable beam, and a secondhydraulic motor drivingly connected to said rotatable turret forrotating said turret, said second hydraulic motor being actuable by saidfirst control means and said remote control means.

9. An aerial device comprising rotatable turret means includinghydraulic drive means for rotation of said turret means, a mast assemblymounted to said turret prising a first hydraulic circuit having firsthydraulic fluid supply means for supplying fluid to said first hydrauliccircuit, said remote control means comprising a second hydraulic circuithaving second hydraulic fluid supply means for supplying fluid to saidsecond hydraulic circuit, .said first and second fluid supply meansbeing noncommunicative with one another, and said first and secondhydraulic circuits being noncommunicative with one another such thatfluid from said first hydraulic circuit does not flow into said secondhydraulic circuit and fluid from said second hydraulic circuit does notflow into said first hydraulic circuit.

10. An aerial device as claimed in claim 9 wherein said first and secondhydraulic fluid supply means each contain different hydraulic fluids.

11. An aerial device as claimed incliam 10 wherein the hydraulic fluidof said first hydraulic fluid supply means is oil and the hydraulicfluid of said second hydraulic fluid supply means is silicone oil.

12. An aerial device comprising a movable beam member having a hydrauliccylinder connected thereto, actuation of said cylinder moving said beam,first control means provided at one station on said aerial device forcontrolling actuation of said hydraulic cylinder, remote control meansprovided at a second station on said device for actuation of said firstcontrol means, said first control means and said remote control meanseach including separate noncommunicative hydraulic circuits, said remotecontrol means including master valve means and said first control meansincluding slave valve means, thehydraulic circuit of said remote controlmeans comprising fluid supply means connected in series to a fluid pump,and first distribution line means connected to said slave valve meansfor distributing fluid therein, said fluid pump being connected inseries to a fluid line junction having second distribution line meansconnecting said junction to said master valve means for distributingfluid therein and a first bridge line connecting said junction to saidfirst distribution line means, the hydraulic circuit of said remotecontrol means further including return line means connecting said mastervalve means and said fluid supply means.

13. An aerial device as claimed in claim 12 wherein the hydrauliccircuit of said remote control means further includes a second bridgeline connecting said first bridge line and said return line means, saidsecond bridge line having valve means for permitting fluid to flow fromsaid first bridge line to said return line means, said valve meanspreventing reverse fluid flow. 14. An aerial device as claimed in claim12 including a pressure relief means on said first bridge lineinterposed between said junction of fluid lines and said firstdistribution line means.

15. An aerial device as claimed in claim 12 wherein the hydrauliccircuit of saidfirst control means includes a hydraulic motor, saidfluid pump. being drivingly connected to said hydraulic motor such thatmovement of said pump is attributable to movement of said hydraulicmotor.

16.An aerial device as claimed in claim 12 wherein the hydraulic circuitof said remote control means further includes valve connection linemeans interconnecting said master valve means and said slave valvemeans.

17. An aerial device as claimed in claim 16 wherein said master valvemeans include a two-way, twoposition master valve and said slave valvemeans include a reciprocable slave valve having at least one fluidchamber, one position of said master valve preventing fluid in saidsecond distribution line means from entering said master valve, said oneposition of said master valve enabing fluid to flow from said firstdistribution line-meansinto said slave valve, through said valveconnection line means into said master valve, and to said return linemeans fQr passage to said fluid supply means. 7

18. An aerial device as claimed in claim 17 wherein said one position ofsaid master valve corresponds to a non-actuated condition of said mastervalve such that fluid flows through said master valve and slave valve,bleeding said valves and causing no movement of said first controlmeans.

19. An aerial device as claimed in claim 17 wherein a second position ofsaid master valve enables fluid to flow into said master valve from saidsecond distribution line means, through said valve connection line meansinto said slave valve, said first distribution line means includingvalve means for preventing fluid flow from said slave valve through saidfirst distribution line means such that fluid flowing into said slavevalve from said valve connection line means accumulates in said slavevalve.

20. An aerial device as claimed in claim '19 wherein said secondposition of said master valve corresponds to an actuated condition ofsaid master valve such that fluid accumulating in said slave valvecauses movement of said slave valve and corresponding movement of saidfirst control means to actuate said hydraulic cylinder, thereby movingsaid movable beam.

21. An aerial device as claimed in claim 19 wherein the hydrauliccircuit 'of said remote control means includes a pressure relief meanson said first bridge line interposed between said junction of fluidlines and said first distribution line means.

22. An aerial device as claimed in claim 21 wherein the hydrauliccircuit of said remote control means further includes a second bridgeline interconnecting said first bridge line and said return line means,said second bridge line having valve means for permitting fluid to flowfrom said first bridge line to said return line, said valve meanspreventing reverse fluid flow.

23. An aerial device as claimed in claim 19 wherein said slave valve andsaid first control means include interconnected movable members. suchthat movement of one of said movable members causes correspondingmovement of saidother movable member and accumulation of fluid in thefluid chamber of said slave valve causes movement of said movablemembers to actuate said hydraulic cylinder, thereby moving said movablebeam.

24. An aerial device as claimed in claim 23 including biasing meansconnected to said movable members for restoring said movable members toa predetermined reference position when said first control means isunactuated and said remote control means master valve is in said oneposition.

25. A method for remotely controlling movement of an aerial device beamby a hydraulic cylinder having direct control hydraulic means comprisingactuating the movementof the direct control hydraulic means with aremote control hydraulic means, separating the fluid supply means forthe remote control hydraulic means from the fluid supply for the directcontrol hydraulic means, and hydraulically separating remote remotecontrol hydraulic fluid with a pump drivingly connected to rotatingmeans within the direct control hydraulic means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 788,125 Dated January 29 197 Inventor(s) y Balogh It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown pelow:

The attorney's name should be --John D. Pope III--. Column 1, line 43,"experinces" should read --experience Column 3, line 41, "mmber" shouldread --member--.

Column 8, line 6 4, "cliam" should read --claim-.

Columng, line 5 4, "enabing" should read enabling-.

Signed and sealed this 6th-day of August 1974.

[SEAL) Attest:

MCCOY M. GIBSON, JR. c. MARSHALL DANN' Attesting Officer Commissioner ofPatents :ORM PC4050 USCOMM-DC 60376-P69 U.5. GOVERNMENY PRINTING OFFICE:I959 O356-334

1. An aerial device comprising a movable beam member having a hydrauliccylinder coNnected thereto, actuation of said cylinder moving said beam,first control means provided at one station on said aerial device forcontrolling actuation of said hydraulic cylinder, and remote controlmeans provided at a second station on said aerial device for actuationof said first control means, said first control means comprising a firsthydraulic circuit having first hydraulic fluid supply means forsupplying fluid to said first hydraulic circuit, said remote controlmeans comprising a second hydraulic circuit having second hydraulicfluid supply means for supplying fluid to said second hydraulic circuit,said first and second fluid supply means being noncommunicative with oneanother, and said first and second hydraulic circuits beingnoncommunicative with one another such that fluid from said firsthydraulic circuit does not flow into said second hydraulic circuit andfluid from said second hydraulic circuit does not flow into said firsthydraulic circuit.
 2. An aerial device as claimed in claim 1 whereinsaid first and second hydaulic fluid supply means each contain differenthydraulic fluids.
 3. An aerial device as claimed in claim 2 wherein thehydraulic fluid of said first hydraulic fluid supply means is petroleumoil and the hydraulic fluid of said second hydraulic fluid supply meansis silicone oil.
 4. An aerial device as claimed in claim 1 wherein saidfirst hydraulic circuit includes a first hydraulic motor, said secondhydraulic circuit including a pump for pumping fluid through said secondhydraulic circuit, said pump being drivingly connected to said firsthydraulic motor such that pump movement is attributable to movement ofsaid hydraulic motor.
 5. An aerial device as claimed in claim 1 furtherincluding slave valve means having a valve member mechanically connectedto said first control means, said slave valve means having hydrauliccommunication with said second hydraulic fluid supply means such thatfluid in said second hydraulic circuit passes through said slave valvemeans and movement of said slave valve member by said second hydraulicfluid effects movement of said first control means through saidmechanical connection to actuate said hydraulic cylinder thereby movingsaid movable beam.
 6. An aerial device as claimed in claim 1 whereinsaid first station is spaced from said beam and said second station isassociated with said beam.
 7. An aerial device as claimed in claim 6wherein said second station comprises a basket connected to said beam.8. An aerial device as claimed in claim 1 further including a rotatableturret for supporting and rotating said movable beam, and a secondhydraulic motor drivingly connected to said rotatable turret forrotating said turret, said second hydraulic motor being actuable by saidfirst control means and said remote control means.
 9. An aerial devicecomprising rotatable turret means including hydraulic drive means forrotation of said turret means, a mast assembly mounted to said turretmeans, a beam member joined to said mast assembly, first control meansprovided at one station on said aerial device for controlling actuationof said hydraulic drive means and remote control means provided at asecond station on said aerial device for actuation of said first controlmeans, said first control means comprising a first hydraulic circuithaving first hydraulic fluid supply means for supplying fluid to saidfirst hydraulic circuit, said remote control means comprising a secondhydraulic circuit having second hydraulic fluid supply means forsupplying fluid to said second hydraulic circuit, said first and secondfluid supply means being noncommunicative with one another, and saidfirst and second hydraulic circuits being noncommunicative with oneanother such that fluid from said first hydraulic circuit does not flowinto said second hydraulic circuit and fluid from said second hydrauliccircuit does not flow into said first hydraulic circuit.
 10. An aerialdevice as claimed in claim 9 wherein said first and second hydraulicfluid supply means each contain different hydraulic fluids.
 11. Anaerial device as claimed in cliam 10 wherein the hydraulic fluid of saidfirst hydraulic fluid supply means is oil and the hydraulic fluid ofsaid second hydraulic fluid supply means is silicone oil.
 12. An aerialdevice comprising a movable beam member having a hydraulic cylinderconnected thereto, actuation of said cylinder moving said beam, firstcontrol means provided at one station on said aerial device forcontrolling actuation of said hydraulic cylinder, remote control meansprovided at a second station on said device for actuation of said firstcontrol means, said first control means and said remote control meanseach including separate noncommunicative hydraulic circuits, said remotecontrol means including master valve means and said first control meansincluding slave valve means, the hydraulic circuit of said remotecontrol means comprising fluid supply means connected in series to afluid pump, and first distribution line means connected to said slavevalve means for distributing fluid therein, said fluid pump beingconnected in series to a fluid line junction having second distributionline means connecting said junction to said master valve means fordistributing fluid therein and a first bridge line connecting saidjunction to said first distribution line means, the hydraulic circuit ofsaid remote control means further including return line means connectingsaid master valve means and said fluid supply means.
 13. An aerialdevice as claimed in claim 12 wherein the hydraulic circuit of saidremote control means further includes a second bridge line connectingsaid first bridge line and said return line means, said second bridgeline having valve means for permitting fluid to flow from said firstbridge line to said return line means, said valve means preventingreverse fluid flow.
 14. An aerial device as claimed in claim 12including a pressure relief means on said first bridge line interposedbetween said junction of fluid lines and said first distribution linemeans.
 15. An aerial device as claimed in claim 12 wherein the hydrauliccircuit of said first control means includes a hydraulic motor, saidfluid pump being drivingly connected to said hydraulic motor such thatmovement of said pump is attributable to movement of said hydraulicmotor.
 16. An aerial device as claimed in claim 12 wherein the hydrauliccircuit of said remote control means further includes valve connectionline means interconnecting said master valve means and said slave valvemeans.
 17. An aerial device as claimed in claim 16 wherein said mastervalve means include a two-way, two-position master valve and said slavevalve means include a reciprocable slave valve having at least one fluidchamber, one position of said master valve preventing fluid in saidsecond distribution line means from entering said master valve, said oneposition of said master valve enabing fluid to flow from said firstdistribution line means into said slave valve, through said valveconnection line means into said master valve, and to said return linemeans for passage to said fluid supply means.
 18. An aerial device asclaimed in claim 17 wherein said one position of said master valvecorresponds to a non-actuated condition of said master valve such thatfluid flows through said master valve and slave valve, bleeding saidvalves and causing no movement of said first control means.
 19. Anaerial device as claimed in claim 17 wherein a second position of saidmaster valve enables fluid to flow into said master valve from saidsecond distribution line means, through said valve connection line meansinto said slave valve, said first distribution line means includingvalve means for preventing fluid flow from said slave valve through saidfirst distribution line means such that fluid flowing into said slavevalve from said valve connection line means accumulates in saiD slavevalve.
 20. An aerial device as claimed in claim 19 wherein said secondposition of said master valve corresponds to an actuated condition ofsaid master valve such that fluid accumulating in said slave valvecauses movement of said slave valve and corresponding movement of saidfirst control means to actuate said hydraulic cylinder, thereby movingsaid movable beam.
 21. An aerial device as claimed in claim 19 whereinthe hydraulic circuit of said remote control means includes a pressurerelief means on said first bridge line interposed between said junctionof fluid lines and said first distribution line means.
 22. An aerialdevice as claimed in claim 21 wherein the hydraulic circuit of saidremote control means further includes a second bridge lineinterconnecting said first bridge line and said return line means, saidsecond bridge line having valve means for permitting fluid to flow fromsaid first bridge line to said return line, said valve means preventingreverse fluid flow.
 23. An aerial device as claimed in claim 19 whereinsaid slave valve and said first control means include interconnectedmovable members such that movement of one of said movable members causescorresponding movement of said other movable member and accumulation offluid in the fluid chamber of said slave valve causes movement of saidmovable members to actuate said hydraulic cylinder, thereby moving saidmovable beam.
 24. An aerial device as claimed in claim 23 includingbiasing means connected to said movable members for restoring saidmovable members to a predetermined reference position when said firstcontrol means is unactuated and said remote control means master valveis in said one position.
 25. A method for remotely controlling movementof an aerial device beam by a hydraulic cylinder having direct controlhydraulic means comprising actuating the movement of the direct controlhydraulic means with a remote control hydraulic means, separating thefluid supply means for the remote control hydraulic means from the fluidsupply for the direct control hydraulic means, and hydraulicallyseparating remote control hydraulic circuitry from direct controlhydraulic circuitry by preventing hydraulic fluid in each respectivehydraulic control means from flowing into the other hydraulic controlmeans.
 26. The method of claim 25 including using a hydraulic fluid inthe remote control circuit having different viscosity characteristicsfrom that of the hydraulic fluid in the direct control hydraulic means.27. The method of claim 25 including pumping the remote controlhydraulic fluid with a pump drivingly connected to rotating means withinthe direct control hydraulic means.